function get_roles_associes(){
	var e = $('id_role')
    e.update("")
    new Ajax.Request('/characters/ajax_get_associated_roles/', { 
    method: 'post',
    parameters: $H({'id_classe':$('id_classe').getValue()}),
    onSuccess: function(transport) {
        var e = $('id_role')
        if(transport.responseText)
            e.update(transport.responseText)
    }
    });
}